LOCATION ELMO MTInactive Series
TAXONOMIC CLASS: Fine, illitic, frigid Natric Camborthids
TYPICAL PEDON: Elmo silty clay loam, in rangeland. (Colors are for dry soil unless otherwise noted.)
E--0 to 3 inches; light gray (10YR 7/2) silty clay loam, grayish brown (10YR5/2) moist; moderate coarse platy structure parting to strong coarse granular; hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine, fine, and medium pores; slightly effervescent; strongly alkaline (pH 8.8); abrupt wavy boundary. (3 to 8 inches thick)
Bw1--3 to 7 inches; very pale brown (10YR 7/3) silty clay, pale brown (10YR6/3) moist; weak coarse prismatic structure parting to strong fine angular blocky; hard, firm, very sticky and very plastic; common very fine and fine roots; common very fine, fine, and medium pores; strongly effervescent; strongly alkaline (pH 8.8); abrupt wavy boundary.
Bw2--7 to 12 inches; very pale brown (10YR 7/3) silty clay loam, pale brown (10YR6/3) moist; weak coarse prismatic structure parting to moderate medium subangular blocky; slightly hard, friable, very sticky and very plastic; common very fine and fine roots; many very fine and fine pores and common medium pores; strongly effervescent; very strongly alkaline (pH9.2); clear wavy boundary. (The Bw horizon is 4 to 10 inches thick.)
Ck--12 to 19 inches; white (10YR 8/2) silty clay loam, very pale brown (10YR 7/3) moist; massive; slightly hard, friable, sticky and plastic; few very fine and fine roots; few fine, very fine, and medium pores; disseminated lime; violently effervescent; very strongly alkaline (pH 9.4); gradual wavy boundary. (6 to 20 inches thick)
C1--19 to 41 inches; white (10YR 8/2) silty clay loam that has strata of silty clay, very pale brown (10YR 7/3) moist; massive breaking to plates 1 inch thick; slightly hard, friable, sticky and plastic; few fine roots; strongly effervescent; very strongly alkaline (pH 9.4); abrupt smooth boundary. (15 to 30 inches thick)
C2--41 to 60 inches; very pale brown (10YR 7/3) silty clay loam that has strata of silty clay, light yellowish brown (10YR 6/4) moist; massive breaking to plates 1 inch thick; hard, firm, very sticky and very plastic; strongly effervescent; very strongly alkaline (pH 9.2). TYPE LOCATION: Lake County, Montana; 2,300 feet south and 1,200 feet east of the NW corner of sec. 11, T.22N., R.22W.
RANGE IN CHARACTERISTICS:
Soil temperature: 43 to 47 degrees F.
Control section: 35 to 50 percent clay
NOTE: Some areas have a dark gray (10YR 4/1) dry horizon at a depth of 2 to 4 inches. This layer is most common on the strongly saline phase. This horizon is 2 to 4 inches thick.
E horizon: Strongly saline
Hue: 10YR
Value, dry: 7 or 8
Value, moist: 5 or 6
Chroma: 2 or 3
Texture, F2 mm: silty clay loam or silt loam
Clay content: 18 to 35 percent
EC: F4.0 mmhos J16 mmhos
SAR: 20 to 45
Reaction: pH 8.5
Bw horizon:
Hue: 10YR
Value, dry: 7 or 8
Value, moist: 4, 5, or 6
Chroma: 2 or 3
Texture, F2 mm: silty clay loam or silty clay
Clay content: 35 to 50 percent
EC: 2 to 8 mmhos 8 to 16 mmhos
SAR: 45 to 100
Reaction: pH J9.0
Ck horizon:
Hue: 10YR
Value, dry: 7 or 8
Value, moist: 6 or 7
Chroma: 2 or 3
Texture, F2 mm: silty clay loam or silty clay
Clay content: 35 to 50 percent
Calcium carbonate equivalent: 10 to 15 percent
EC: F4.0 mmhos4 to 8 mmhos
SAR: 45 to 100
Reaction: pH J9.0
C1 and C2 horizons: Strongly saline
Hue: 10YR
Value, dry: 7 or 8
Value, moist: 5, 6, or 7
Chroma: 2, 3, or 4
Texture, F2 mm: silty clay loam or silty clay
Clay content: 35 to 50 percent
EC: F4 mmhos 4 to 8 mmhos
SAR: 45 to 120
Reaction: pH J9.0
COMPETING SERIES: There are no series in the same family. A similar soil is Round Butte, which has an argillic horizon.
GEOGRAPHIC SETTING: Elmo soils are on terraces and in drainageways. Elevations are 2,600 to 3,000 feet. Slopes are 0 to 5 percent. These soils formed in clayey lacustrine deposits. The climate is characterized by long cold winters, moist falls and springs, and warm dry summers. Mean annual precipitation is 10 to 14 inches. Mean annual temperature is 41 to 45 degrees F. The frost-free season is 105 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Irvine, Lonepine, and Round Butte soils. The Irvine soils have little development and lack a Bw or Ck horizon. The Lonepine soils have a fine-silty control section. The Round Butte soils have an argillic horizon.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; very slow permeability.
USE AND VEGETATION: Used mainly as rangeland. The potential native vegetation is basin wildrye, alkali bluegrass, inland saltgrass, alkali sacaton, and western wheatgrass.
DISTRIBUTION AND EXTENT: Western Montana. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Lake County, Montana, 1982.
REMARKS: Named after a small town in Lake County, Montana.